Amido-And Carboxyl-Based Of Polypeptoid By Clcik Chemistry Of Thiol-Ene/Yne

Polypeptoids are a promising class of peptidomimetic polymers based on an N-substituted glycine backbone.They offer great advantageous properties for both fundamental research and applications in biotechnology.Due to the similarity in structure to polypeptides,the polypeptoids exhibit excellent biocompatibility and potential bioactivities.The lack of inter-and intrachain hydrogen bonding and chirality in the main chain results in a potentially flexible backbone.The properties of polypeptoids are mainly dominated by the sidechain identity,which offers a unique and facile way to tailor the properties of the polymers by structural design of the side chains.Further,the polypeptoids are highly designable in terms of synthetic approaches.In addition to solid-phase method,the ring-opening polymerization(ROP)has emerged as an effective method to produce the polypeptoids with high molecular weights in high yields.The postmodification of the welldefined polypeptoid precursors offer a convenient method to prepare polypeptoids with versatile functionalities.1.Stimuli-responsive polymers have received increasing interest for a variety of applications.Here,we report a seriesof unique charge-determined thermoresponsive polypeptoids synthesized by a combination of ring-opening polymerization andclick chemistry.The LCST-type and UCST-type behavior is mainly dominated by the charge state on the side chain.Further,thephase transition temperature highly depends on the degree of polymerization,the side-chain architecture,the pH value,and soon.The obtained polypeptoid solutions exhibit good stability against temperature and salt concentration.To our knowledge,this report presents the first charge-determined LCST/UCST-type polymer from identical homopolymer backbone that displays awide range of tunable cloudy points in aqueous media.We propose the hydrogen-bonding interaction plays a critical part on thesolution behavior.These features make polypeptoids ideal candidates for highly designable stimuli-responsive polymeric materials.2.Antimicrobial peptides(AMPs)have attracted much attention since its initial discovery due to their advantages over no-drug resistance and rapid bacteria killing.Compared to peptides,peptoids were more stable to enzymic hydrolysis,giving a long-term stability in the creature.Thus peptoids show great potentials in long period bacteria resisting in vivo.Here,we combined the superiority of natural antimicrobial peptides and peptoids for antibacterial applications.A series of polypeptoids consisting of hydrophobic chain and hydrophilic primary amine chain were synthesized by ring-opening polymerization of N-carboxyanhydride(NCA)and post-modification.These polypeptoids showed antimicrobial activity to three bacteria(Staphylococcus aureus,Escherichia coli,Pseudomonas aeruginosa).In hemolysis testing,the hemolysis of several samples decreased at high concentration of polymer solution,possibly due to the aggregation.Above all,polypeptoid coated on polydimethylsiloxane(PDMS)and then planted in rats could exhibit excellent antibacterial effect for up to 5 days.Namely,most of polypeptoids synthesized in this work could be widely used as surface coating materials to suppress surface bacteria growth.In addition,the successful applications polypeptoids in antisepsis may bring new perspectives to this field and more relevant explorations are in progress.